An Adaptive Voltage Control Method for Renewable Energy Systems Considering Voltage Stability Index

With the high penetration of renewable energy integration, modern power systems have gradually exhibited low inertia and weak voltage support characteristics, with frequent transient disturbances such as voltage sags. Traditional fixed-parameter control struggles to balance reactive power support and transient stability, often leading to problems such as insufficient reactive power margin and output current distortion. To address this issue, this paper proposes an adaptive control strategy suitable for Low Voltage Ride-Through (LVRT). By real-time tracking the transient changes of system voltage, the strategy dynamically adjusts the reactive power output reference value and control parameters, enabling accurate adaptation to system operating conditions without modifying the original control structure. Verified by simulation experiments, during the voltage sag interval of 0.3-0.7 s, the application of this control strategy significantly reduces the distortion degree of the output current waveform and narrows the amplitude fluctuation range; the reactive power margin increases from 0.258 p.u. to 0.261 p.u., and the voltage sag depth improves from 0.16 p.u. to 0.32 p.u.; the Transient Voltage Stability Index (TVSI_r) decreases from 0.336 p.u.•s to 0.272 p.u.•s, effectively reducing the cumulative harm of transient voltage recovery. The research results demonstrate that the proposed adaptive control strategy can enhance voltage support capability by improving the reactive power margin, optimize current output characteristics simultaneously, and strengthen the system's anti-disturbance ability against voltage sags, providing technical support for the transient operation stability and equipment safety of power systems.